Write an equation (if possible) of a parabola that satisfies the following conditions:

1. An even function.

   Answer (a):

   Any parabola with a vertex on the $y$-axis. Example: $f\left(x\right) = x^{2} − 3$

2. An odd function.

   Answer (b):

   Impossible

3. Neither even nor odd.

   Answer (c):

   Any parabola with a vertex not on the $y$-axis. Example: $f\left(x\right) = 2x^{2} − 8x + 5$